Interactive effects between water temperature, microparticle compositions, and fiber types on the marine keystone species Americamysis bahia

Recently, there has been an increasing emphasis on examining the ecotoxicological effects of anthropogenic microparticles (MPs), especially microplastic particles, and related issues. Nevertheless, a notable deficiency exists in our understanding of the consequences on marine organisms, specifically in relation to microfibers and the combined influence of MPs and temperature. In this investigation, mysid shrimp (Americamysis bahia), an important species and prey item in estuarine and marine food webs, were subjected to four separate experimental trials involving fibers (cotton, nylon, polyester, hemp; 3 particles/ml; approximately 200 μm in length) or fragments (low-density Polyethylene: LDPE, polylactic acid: PLA, and their leachates; 5, 50, 200, 500 particles/ml; 1-20 μm). To consider the effects in the context of climate change, three different temperatures (22, 25, and 28 °C) were examined. Organismal growth and swimming behavior were measured following exposure to fragments and microfibers, and reactive oxygen species and particle uptake were investigated after microfiber exposure. To simulate the physical characteristics of MP exposure, such as microfibers obstructing the gills, we also assessed the post-fiber-exposure swimming behavior in an oxygen-depleted environment. Data revealed negligible fragment, but fiber exposure effects on growth. PLA leachate triggered higher activity at 25 °C and 28 °C; LDPE exposures led to decreased activity at 28 °C. Cotton exposures led to fewer behavioral differences compared to controls than other fiber types. The exposure to hemp fibers resulted in significant ROS increases at 28 °C. Microfibers were predominantly located within the gastric and upper gastrointestinal tract, suggesting extended periods of residence and the potential for obstructive phenomena over the longer term. The combination of increasing water temperatures, microplastic influx, and oxidative stress has the potential to pose risks to all components of marine and aquatic food webs.

Micron-size tire tread particles leach organic compounds at higher rates than centimeter-size particles: Compound identification and profile comparison

Tire tread particles (TTP) are environmentally prevalent microplastics and generate toxic aqueous leachate. We determined the total carbon and nitrogen leachate concentrations and chemical profiles from micron (∼32 μm) and centimeter (∼1 cm) TTP leachate over 12 days. Dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) were used to measure the concentration of leached compounds. Nontargeted chemical analysis by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC/TOF-MS) was used to compare the chemical profiles of leachates. After leaching for 12 days, DOC was 4.0 times higher in the micron TTP leachate than in the centimeter TTP leachate, and TDN was 2.6 times higher. The total GC×GC/TOF-MS chromatographic feature peak area was 2.9 times greater in the micron TTP leachate than the centimeter TTP leachate, and similarly, the total relative abundance of 54 tentatively identified compounds was 3.3 times greater. We identified frequently measured tire-related chemicals, such as 6PPD, N-cyclohexyl-N'-phenylurea (CPU), and hexa(methoxymethyl)melamine (HMMM), but nearly 50% of detected chemicals were not previously reported in tire literature or lacked toxicity information. Overall, the results demonstrate that smaller TTP have a greater potential to leach chemicals into aquatic systems, but a significant portion of these chemicals are not well-studied and require further risk assessment.

Effect of modifiable risk factors in Parkinson's disease: A case-control study looking at common dietary factors, toxicants, and anti-inflammatory medications

OBJECTIVE

To investigate how common modifiable exposures, including dietary factors, select toxicants, and anti-inflammatory medications, may affect Parkinson's disease.

METHODS

Using surveys, a case-control study was conducted at a medical center, comparing Parkinson's disease patients (N  =  149) and healthy controls (N  =  105). Subjects reported exposure to red meats, vegetables, alcohol, tobacco, anti-inflammatory medications, and pesticides. The relationship between exposures and Parkinson's disease diagnosis was analyzed by logistic regression to generate odds ratio and 95% confidence interval.

RESULTS

Consuming red meat "sometimes" or "always" was positively associated with Parkinson's disease as compared to eating red meats "rarely" or "never"; (odds ratio  =   2.15, 95% confidence interval   =   1.06, 4.39; p  =  0.03) and (odds ratio   =   4.47, 95% confidence interval   =   1.67, 11.94; p  =  0.003), respectively. Exposure to pesticides showed a positive association with Parkinson's disease (odds ratio  =   2.84, 95% confidence interval   =   1.34, 6.00; p  =  0.007). "Always" use of aspirin was inversely associated with Parkinson's disease (odds ratio  =   0.32, 95% confidence interval   =   0.14, 0.70; p  =  0.004). "Ever" having used anti-histamines was inversely associated with Parkinson's disease (odds ratio  =   0.37, 95% confidence interval  =  0.17, 0.81; p  =  0.01).

DISCUSSION

Our study suggests that there are modifiable external factors that are associated with Parkinson's disease. The present study can thus assist clinicians, policy makers, and people living with Parkinson's disease in improving the experience and management of Parkinson's disease.

Operational Performance of a Compact Proton Therapy System: A 5-Year Experience

Purpose

We present an analysis of various operational metrics for a novel compact proton therapy system, including clinical case mix, subsystems utilization, and quality assurance trends in beam delivery parameters over a period of 5 years.

Materials and Methods

Patient-specific data from a total of 850 patients (25,567 fractions) have been collected and analyzed. The patient mix include a variety of simple, intermediate, and complex cases. Beam-specific delivery parameters for a total of 3585 beams were analyzed. In-room imaging system usage for off-line adaptive purpose is reported. We also report key machine performances metrics based on routine quality assurance in addition to uptime.

Results

Our analysis shows that system subcomponents including gantry and patient positioning system have maintained a tight mechanical tolerance over the 5-year period. Various beam parameters were all within acceptable tolerances with no clear trends. Utilization frequency histograms of gantry and patient positioning system show that only a small fraction of all available angles was used for patient deliveries with cardinal angels as the most usable. Similarly, beam-specific metrics, such as range, modulation, and air gaps, were clustered unevenly over the available range indicating that this compact system was more than capable to treat the complex variety of tumors of our patient mix.

Conclusion

Our data show that this compact system is versatile, robust, and capable of delivering complex treatments like a large full-gantry system. Utilization data show that a fraction of all subcomponents range of angular motion has been used. Compilation of beam-specific metrics, such as range and modulation, show uneven distributions with specific clustering over the entire usable range. Our findings could be used to further optimize the performance and cost-effectiveness of future compact proton systems.

Internalization, reduced growth, and behavioral effects following exposure to micro and nano tire particles in two estuarine indicator species

Synthetic rubber emissions from automobile tires are common in aquatic ecosystems. To assess potential impacts on exposed organisms, early life stages of the estuarine indicator species Inland Silverside (Menidia beryllina) and mysid shrimp (Americamysis bahia) were exposed to three tire particle (TP) concentrations at micro and nano size fractions (0.0038, 0.0378 and 3.778 mg/L in mass concentrations for micro size particles), and separately to leachate, across a 5-25 PSU salinity gradient. Following exposure, M. beryllina and A. bahia had significantly altered swimming behaviors, such as increased freezing, changes in positioning, and total distance moved, which could lead to an increased risk of predation and foraging challenges in the wild. Growth for both A. bahia and M. beryllina was reduced in a concentration-dependent manner when exposed to micro-TP, whereas M. beryllina also demonstrated reduced growth when exposed to nano-TP (except lowest concentration). TP internalization was dependent on the exposure salinity in both taxa. The presence of adverse effects in M. beryllina and A. bahia indicate that even at current environmental levels of tire-related pollution, which are expected to continue to increase, aquatic ecosystems may be experiencing negative impacts.

Medical Student Perspectives on Their Role as Emerging Physicians During the COVID-19 Pandemic

The COVID-19 pandemic caused a large strain on the US medical system, with shortage of medical personnel being a key issue. The role of medical school students during a pandemic is not well established. Understanding the perspectives of medical students with regard to their role is essential in determining how to facilitate the use of their skills in combating the pandemic. To evaluate medical student perspectives on the COVID-19 pandemic, an anonymous online survey was distributed to medical students, primarily in the Northeastern United States. In the sample of 232 students, there were significant differences between students in different class years when assessing moral obligations to assist with the COVID-19 pandemic (p = 0.002). A higher percentage of first and second year medical students (pre-clinical training, around 48%) felt that healthcare students are morally obligated to assist as compared to third and fourth year students (clinical training, 30.43% of third years and 23.19% of fourth years). In all class years, the majority said they would regret their decision if they had chosen not to study medicine (62.32% to 79.31%) and most students did not feel their motivation to become a physician had been decreased (84.78% to 87.50%). Though the study was limited because the majority of subjects were from New York, the results provide insight into medical students' attitudes about the COVID-19 pandemic and can be used in the planning of how best to utilize medical students in this and in future situations.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s40670-021-01374-z.

The role of mask mandates, stay at home orders and school closure in curbing the COVID-19 pandemic prior to vaccination

BACKGROUND

COVID-19 has quickly spread throughout the world, necessitating assessment of effective containment methods. The purpose of this study was to examine the impact of government mandated school closures, stay at home orders and mask requirements METHODS: Cumulative incidence rates were calculated at 14-day intervals until the day of the first vaccine administration in the country. Rate ratios were calculated using negative binomial regression while investigating the effects of adjusting for several sociodemographic and medical factors RESULTS: Faster implementation of mask mandates was consistently shown to be protective. States with mask mandates made at three to six months had a 1.61 times higher rate than those who implemented within one month (adjusted rate ratio = 1.61, 95% confidence interval: 1.23-2.10, P = .001). States with mask mandates made after 6 months or with no mandate had a 2.16 times higher rate than those who implemented within 1 month (adjusted rate ratio = 2.16, 95% confidence interval: 1.64-2.88, P < .0001). In contrast, both stay at home orders and school closures had no significant influence on disease trajectory.

DISCUSSION

The benefits of mask mandates are apparent, especially when mandates were issued within a month. The impact of school closing and stay at home orders were less clear.

CONCLUSIONS

Our results suggest that of the different physical distancing measures implemented by the government, mask mandates are the most important.

Defining the Contribution of Adipocyte Subpopulations to Dermal White Adipose Tissue

Introduction: Our lab has previously identified three distinct subtypes of developmentally and functionally white adipocytes and have shown that they each differentially contribute to adipose depots (Lee, KY et al. EMBO J. 2019). Dermal white adipose tissue (dWAT), a layer of adipocytes embedded in the skin below the dermis, has recently been shown to play a role in crucial physiologic processes including thermogenesis, the regulation of aging, scar formation, and wound healing. The purpose of this proposal is to investigate the contribution of three adipocyte subtypes to dWAT. Objectives: The primary objectives of this project are to determine the number of preadipocytes and adipocytes from each of three subtypes present in dWAT. Methodology: Lineage tracing analysis was performed by crossing transgenic mice harboring cre-recombinase under the control of promoter/enhancer elements of each of the three marker genes, Wilms tumor 1, transgelin, or myoxovirus 1 to dual- fluorescent reporter mice. These three mice lines mark Type 1–3 preadipocytes and adipocytes, respectively. dWAT was collected from X week old mice, and adipocyte identities were determined by confocal microscopy. Preadipocyte contribution of these subpopulations was determined by FACS analysis. Results: We found that Type 2 (~45%) and Type 3 (~25%), but not Type 1 preadipocytes significantly contributed to the dWAT preadipocyte cellular population. We also found a similar pattern for the adipocyte populations. Type 1, 2, and 3 adipocytes were found to comprise ~3%, 17%, and 7% of mature adipocytes, respectively. These studies demonstrate that Type 2 and Type 3 adipocytes contribute to the composition of dWAT. Summary/Conclusion: These studies demonstrate that Type 2 and Type 3 adipocytes and preadipocytes significantly contribute to the composition of dWAT. Since these adipocyte subpopulations have different functional properties, including metabolism and response to inflammatory cytokines, the contribution of these adipocyte subtypes may impact the crucial physiologic processes mediated by dWAT.

Growth hormone controls lipolysis by regulation of FSP27 expression

Growth hormone (GH) has long been known to stimulate lipolysis and insulin resistance; however, the molecular mechanisms underlying these effects are unknown. In the present study, we demonstrate that GH acutely induces lipolysis in cultured adipocytes. This effect is secondary to the reduced expression of a negative regulator of lipolysis, fat-specific protein 27 (FSP27; aka Cidec) at both the mRNA and protein levels. These effects are mimicked in vivo as transgenic overexpression of GH leads to a reduction of FSP27 expression. Mechanistically, we show GH modulation of FSP27 expression is mediated through activation of both MEK/ERK- and STAT5-dependent intracellular signaling. These two molecular pathways interact to differentially manipulate peroxisome proliferator-activated receptor gamma activity (PPARγ) on the FSP27 promoter. Furthermore, overexpression of FSP27 is sufficient to fully suppress GH-induced lipolysis and insulin resistance in cultured adipocytes. Taken together, these data decipher a molecular mechanism by which GH acutely regulates lipolysis and insulin resistance in adipocytes.

Clinical associations of proinflammatory cytokines, oxidative biomarkers and vitamin D levels in systemic lupus erythematosus

Background The abnormal biological activity of cytokines plays an important role in the pathophysiology of both systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS). Several studies have highlighted the association of vitamin D and certain pro-inflammatory cytokines with disease activity in SLE. However, there are limited data on the association of vitamin D and antiphospholipid antibodies (aPL) with various proinflammatory biomarkers in these patients and their relative impact on clinical outcomes. Methods The serum levels of several aPL, 25-hydroxy-vitamin D, pro-inflammatory cytokines including IFNα, IL-1β, IL-6, IL-8, IP10, sCD40L, TNFα and VEGF were measured in 312 SLE patients from the Jamaican ( n = 45) and Hopkins ( n = 267) lupus cohorts using commercial Milliplex and ELISA assays. Oxidized LDL/β2glycoprotein antigenic complexes (oxLβ2Ag) and their associated antibodies were also measured in the Jamaican cohort. Healthy controls for oxidative marker and cytokine testing were used. Results Abnormally low vitamin D levels were present in 61.4% and 73.3% of Hopkins and Jamaican SLE patients, respectively. Median concentrations of IP10, TNFα, sCD40L and VEGF were elevated in both cohorts, oxLβ2Ag and IL-6 were elevated in the Jamaican cohort, and IFNα, IL-1β and IL-8 were the same or lower in both cohorts compared to controls. IP10 and VEGF were independent predictors of disease activity, aPL, IP10 and IL-6 were independent predictors of thrombosis and IL-8, and low vitamin D were independent predictors of pregnancy morbidity despite there being no association of vitamin D with pro-inflammatory cytokines. Conclusions Our results indicate that aPL-mediated pro-inflammatory cytokine production is likely a major mechanism of thrombus development in SLE patients. We provide presumptive evidence of the role IL-8 and hypovitaminosis D play in obstetric pathology in SLE but further studies are required to characterize the subtle complexities of vitamin D's relationship with cytokine production and disease activity in these patients.

Physician Risk Assessment Knowledge Regarding BRCA Genetics Testing

The study aim was to evaluate the association between genetics referrals, training in medical school, residency, or continuing medical education and physician knowledge of hereditary breast and ovarian cancer (HBOC). A survey of 55 questions was administered to 140 physicians evaluating knowledge and practice patterns regarding HBOC. Physicians with genetics training during residency were more likely to recognize that most instances of ovarian cancer are not hereditary (odds ratio (OR) = 3.16; 95 % confidence interval (CI) 1.32, 7.58). Physicians with continuing medical education (CME) training on genetics were more likely to identify that screening can be improved for those with a hereditary mutation (OR = 4.28; 95 % CI 1.32, 13.90). Primary care physicians who frequently referred for genetics were more likely to recognize that maternal history is not more important than paternal history (OR = 2.51; 95 % CI 1.11, 5.66), that screening can be improved for those with hereditary risk (OR = 4.06; 95 % CI 1.08, 15.22), and that females with a hereditary breast cancer risk would have different recommendations for screening than someone without this risk (OR = 4.91; 95 % CI 1.04, 23.25). Our data suggest that training and frequency of genetics referrals may be associated with knowledge of general risk assessment for HBOC.

Impact of academic affiliation and training on knowledge of hereditary colorectal cancer

BACKGROUND

Knowledge about hereditary colorectal cancer (CRC) can aid cancer screening and prevention in high-risk patients. Genetic testing, once conducted primarily at academic centers, is now routinely performed in a variety of clinics. Nonacademic physicians may not be aware of hereditary CRC standards of care.

METHODS

From August to November 2012, a survey was administered to predominantly primary care physicians evaluating academic center affiliation, past training in genetics and knowledge regarding hereditary CRC.

RESULTS

One hundred forty physicians completed the survey. Knowledge of hereditary CRC was neither associated with academic affiliation nor with training during medical school or residency, but with continuing medical education (CME) training. Those with CME training were more likely to know that screening could be enhanced for patients with a hereditary cancer risk (OR = 4.49, 95% CI = 1.40-14.38) and that an individual with hereditary CRC would have different screening recommendations (OR = 7.49, 95% CI = 1.37-40.81). Residency training and CME training were associated with more frequent hereditary risk assessment.

CONCLUSION

Genetics training may be associated with physicians' knowledge and assessment of hereditary CRC. Training at the CME level in particular may be integral to the delivery of genetic services in clinical practice.

Interpreting the biological relevance of bioinformatic analyses with T-DNA sequence for protein allergenicity

Global regulatory agencies require bioinformatic sequence analysis as part of their safety evaluation for transgenic crops. Analysis typically focuses on encoded proteins and adjacent endogenous flanking sequences. Recently, regulatory expectations have expanded to include all reading frames of the inserted DNA. The intent is to provide biologically relevant results that can be used in the overall assessment of safety. This paper evaluates the relevance of assessing the allergenic potential of all DNA reading frames found in common food genes using methods considered for the analysis of T-DNA sequences used in transgenic crops. FASTA and BLASTX algorithms were used to compare genes from maize, rice, soybean, cucumber, melon, watermelon, and tomato using international regulatory guidance. Results show that BLASTX for maize yielded 7254 alignments that exceeded allergen similarity thresholds and 210,772 alignments that matched eight or more consecutive amino acids with an allergen; other crops produced similar results. This analysis suggests that each nontransgenic crop has a much greater potential for allergenic risk than what has been observed clinically. We demonstrate that a meaningful safety assessment is unlikely to be provided by using methods with inherently high frequencies of false positive alignments when broadly applied to all reading frames of DNA sequence.

Using Layered Manufacturing to Create Textured Microstructures in Si3N4 Ceramics

In recent years, seeding has been shown to be an effective method to create textured microstructures in Si 3N4, Al2O3 and PZT ceramics. The objective of this research is to create anisotropic and textured Si3N4 parts using the Fused Deposition of Ceramics (FDC) process. This technique is currently being developed to fabricate high performance structural Si 3N4 based components. In order to create the textured microstructures, rod-like β-Si3N4 seed particles are introduced into the FDC feedstock filaments. In this study, anisometric β-Si3N4 seeds were introduced into the starting α-Si3N4 powder (Honeywell's AS800 grade) at a 10 vol.% loading. The effects of the seeds (aspect ratio ∼4) on the viscosity and resultant microstructure were evaluated using capillary rheology, scanning electron microscopy, coefficient of thermal expansion (CTE) measurements, and x-ray diffraction. It is observed that the seeds do align during filament extrusion and a significant texture has been detected by x-ray diffraction and CTE measurements in FDC feedstock filaments and sintered FDC parts.

Process-Property-Performance Relationship for Fused Deposition of Ceramics (FDC) Feedstock Materials

Fused deposition of ceramics (FDC) is an extrusion based layered manufacturing process. It uses a high solids loaded (>50 vol. % ceramic or metal powder) thermoplastic binder in filament form as the feedstock material. The filament acts as both the piston driving the extrusion process and the feedstock material being deposited in the X-Y direction onto a Z-stage platform. The primary mode of failure of the filament during the FDC process is via buckling. Earlier work has shown that the filament compressive modulus and the feedstock viscosity control the buckling behavior of the filament material in FDC. A study was conducted to investigate the effect of particle/polymer interface on the viscosity and compressive modulus of the PZT filled ECG9 system. The relative viscosity of the untreated and the surface treated particle filled systems increases with solids loading. It is found that both of the surface treated materials (stearic acid and titanate coupling agent) exhibit a lower relative viscosity than the untreated material. A rheological model (Krieger-Dougherty model) was used to investigate the possible reasons for the decrease in relative viscosity due to the surface treatment of particles. The investigaton showed that the coupling agent acted as a dispersant (increasing value of ϕm) and thereby decreased the viscosity. The stearic acid may act as a dispersant (increasing value of ϕm) and as a lubricant (decreasing value of KE). The compressive modulus of all the different systems studied showed an increase with solids loading. A generalized Nielsen model was used to describe the relative modulus vs. solids loading behavior for all the different systems studied. Also, the measured compressive modulus of the filled system was found to be insensitive to the modifications in the particle surface treatment.

Bacillus anthracis spore suspensions: determination of stability and comparison of enumeration techniques

AIM

To determine the stability and variability in concentration of spore suspensions of Bacillus anthracis (BA) spore suspensions by comparing different methods of enumeration and to detect changes, if any, under different storage conditions.

METHODS AND RESULTS

Plate and microscope counts were compared to measuring the genomic equivalents based on DNA content BA spore suspensions. We developed chemical methods to extract spore DNA and extra-spore (ES) DNA. DNA mass was determined by gel electrophoresis and QPCR assays were developed using the markers on the chromosome (rpoB) and the pXO1 plasmid (pag). The plate counts and microscope counts were very stable (for up to 900 days). The effect of freezing and the presence of additives in samples were tested for up to 300 days, and the results indicated that the additives tested and freezing did not decrease the viability or microscope counts.

CONCLUSIONS

Bacillus anthracis spore suspensions can be stored for long periods of time without significant loss of viability or clumping. The content of ES DNA was variable and changed with time.

SIGNIFICANT AND IMPACT OF THE STUDY

The study shows that BA spore suspensions can be developed for reference materials providing a uniform basis for comparing detection equipment and results from different laboratories.

Diagnostic adequacy and accuracy of fine needle aspiration cytology in neck lump assessment: results from a regional cancer network over a one year period

Aim: To establish the diagnostic accuracy and adequacy of fine needle aspiration cytology (FNAC) within a regional cancer network, and to determine what service improvements may be required to allow successful implementation of an FNAC-based, ‘one-stop’ head and neck clinic, as proposed by the current National Institute for Clinical Excellence guidelines.

Materials and methods: The Sussex cancer network serves a population of 1 200 000 and contains five hospitals within three acute trusts. In 2004, an audit was undertaken retrospectively to examine the diagnostic adequacy and accuracy of head and neck FNAC across the network. Comparisons were then made with the results of subsequent relevant surgery. For the purposes of the audit, FNAC was subdivided into three main groups: salivary gland, thyroid gland and neck node. As part of the data analysis, we also noted the clinical source of the FNAC and whether it was performed blind or under image guidance.

Results: In 2004, 712 FNAC procedures were undertaken in 647 patients, 276 of whom underwent subsequent surgery. Fine needle aspiration cytology was non-diagnostic in 52 per cent of patients in the neck node group, in 50 per cent in the salivary gland group and in 30 per cent in the thyroid group. With these non-diagnostic results removed, statistical analysis was performed on data from those patients who had undergone both FNAC and subsequent surgery. This gave a sensitivity of 89 per cent and a specificity of 57 per cent in the neck node group, a sensitivity of 64 per cent and specificity of 100 per cent in the salivary gland group, and a sensitivity of 62 per cent and specificity of 86 per cent in the thyroid group. Diagnostic problems with FNAC were noted, particularly in the differentiation of reactive nodal hyperplasia from lymphoma and in diagnosing follicular thyroid lesions. Ultrasound guidance was used in 50 per cent of the thyroid FNAC procedures but in only a minority of patients in the neck node and salivary gland groups.

Conclusion: This audit demonstrated widespread diagnostic difficulties associated with head and neck FNAC in a large patient sample. It is likely that these problems will be mirrored in other cancer networks. In order for one-stop head and neck clinics to succeed, the non-diagnostic rate of FNAC in particular must be minimised. There are strategies to enable this, depending on local resources, including increased access to cytologists or cytology technicians, diagnostic ultrasound, image guidance for FNAC and the use of ultrasound-guided core biopsy.

Endocarditis and ulnar artery aneurysm as presenting features of antiphospholipid syndrome and polyarteritis nodosa

Antiphospholipid syndrome in association with vasculitis is highlighted in this report. The combination of thrombotic and inflammatory processes resulted in endocarditis, aneurysm formation and thrombosis. To our knowledge this is the first presentation of a large vessel aneurysm in these conditions. Anticoagulation and immunosuppression are the treatment modalities of choice.

Barmah-Millewa forest environmental water allocation

The formal allocation of water for the environment is a developing area of river management both scientifically and in terms of community participation. This case study, illustrating the recent use of the Barmah-Millewa Forest Environmental Water Allocation (EWA), provides a practical demonstration of community participation in environmental water management, the application of hydrological and biological "triggers" and a positive, demonstrable biological outcome from an environmental water allocation. The Barmah-Millewa Forest covers an area of 70,000 ha across the floodplain of the Murray River, upstream of the town of Echuca. About half the forest is in NSW (Millewa) and half is in Victoria (Barmah). The Barmah Forest is a Wetland of International Importance listed under the Convention on Wetlands - Ramsar Convention. The forest is the largest river redgum forest in the world. The natural flooding cycle associated with the forest has been significantly altered by regulation of the Murray River--impacting upon the overall health of the forest ecosystem. Recognising this, the Murray Darling Basin Commission developed a water management strategy for the forest to enhance forest, fish and wildlife values. To implement this strategy, between 1990 and 1993 reports were completed and community consultation took place. In 1993 the Murray Darling Basin Ministerial Council approved allocation of 100 Gigalitres of water per year, provided in equal shares by NSW and Victoria, to meet the needs of the forest ecosystem and in 1994 the Barmah-Millewa Forum was established under the Murray-Darling Basin Agreement. The vision for the Forum is to maintain and, where possible, improve the ecological and productive sustainability of the Barmah-Millewa Forest and to establish a planning and operational framework to better meet the flooding and drying requirements of the riparian forests and wetlands. Between October 2000 and January 2001 the Barmah-Millewa Forest Environmental Water Allocation was used for the second time. A total of 341 GL was released as an EWA. This amount represented only 8% of the total flows downstream of Yarrawonga Weir from September 2000 and January 2001. The strategic use of the relatively small amount of water enabled flooding to be maintained and ensured significant breeding success for water birds and other biota in the Forest.

Pathologic correlates of increased signals of the centrum ovale on magnetic resonance imaging

The pathologic correlates of increased signal in the white matter of the centrum ovale in postmortem magnetic resonance imaging were investigated in an unselected series of 15 autopsies. Two types of magnetic resonance imaging hyperintensities could be separated on the basis of size (10-mm cutoff): extensive and punctate. The pathologic basis of extensive hyperintensities was large areas of pallor with ill-defined margins, located in the central white matter and sparing the subcortical U fibers on both myelin and axonal stains. Microscopically, these areas showed diffuse vacuolation and significant reduction in the areal densities of glial cells. This change was never seen in areas that did not show extensive white matter hyperdensities on magnetic resonance imaging. The correlates of punctate magnetic resonance imaging hyperintensities were less well defined; dilated Virchow-Robin spaces probably represent a common cause of this phenomenon.

Transparenchymal suture fixation and testicular histology in a prepubertal rat model

We evaluate the effect on testicular histology when fine suture materials are used for transparenchymal suture fixation of the testis during orchiopexy in immature Sprague-Dawley rats. Significant inflammatory reactions were observed in all groups of animals with suture fixation regardless of suture size and material. Only 5% of the animals in the dartos pouch control group had an inflammatory response and no inflammation was noted in the nonoperative controls. Although these findings have not been documented in humans, this evidence raises concerns about the impact of surgical technique on the future reproductive capabilities of these testes. Alternatives to transparenchymal suture fixation of the testis should be considered in patients with cryptorchidism and testicular torsion. Sutureless dartos pouch placement may provide adequate fixation during most orchiopexies without risking injury to testicular structure and function.

Comparison of the University of Wisconsin preservation solution and other crystalloid perfusates in a 30-hour rabbit lung preservation model

The University of Wisconsin solution, which contains a high potassium concentration (120 mmol/L), was evaluated for rabbit lung preservation by comparing it with a modified University of Wisconsin solution with low potassium (4 mmol/L), a low-potassium dextran solution (4 mmol/L), and simple surface cooling. In the first three groups rabbit lungs were flushed in situ with the solution (n = 5 in each group); then the lung-heart block was harvested and stored at 10 degrees C for 30 hours. In the surface cooling group the lungs were harvested without flushing and then simply immersed in saline and stored. For assessment, the stored lung was ventilated with room air and perfused with fresh venous blood at a rate of 40 ml/min for 10 minutes. Assessment of lung function included gas analysis of effluent blood, mean pulmonary artery perfusion pressure, and peak airway pressure. Among these parameters, oxygen tension was most sensitive. Oxygen tension at 10 minutes' perfusion in the modified University of Wisconsin (95 +/- 6 mm Hg) and low-potassium dextran (99 +/- 4 mm Hg) groups was significantly higher than that in the surface cooling (61 +/- 7 mm Hg) and University of Wisconsin (51 +/- 7 mm Hg) groups. There was no difference between the modified University of Wisconsin and low-potassium dextran groups or between the surface cooling and University of Wisconsin groups. We conclude that the low-potassium University of Wisconsin solution is superior to the high-potassium University of Wisconsin solution and that the lactobionate and raffinose included in the University of Wisconsin solution as impermeants do not improve lung preservation in this model.

Influence of intraalveolar oxygen concentration on lung preservation in a rabbit model

We previously reported the use of an inexpensive screening model for lung preservation involving ventilation and perfusion of excised rabbit lungs after their preservation. We now have extended this model by perfusing the preserved lung in cross circulation with an anesthetized rabbit to permit stable reperfusion of the preserved lungs for 60 minutes. With this model we compared the results of lung preservation with the lungs inflated with nitrogen, room air, or 100% oxygen during 24 hours of hypothermic storage. Four groups of animals were studied: group 1, excision and immediate evaluation; group 2, inflation with room air and storage for 24 hours at 10 degrees C; group 3, same as group 2, with 100% oxygen for inflation during storage; group 4, same as group 2, with 100% nitrogen for inflation during storage. Assessment of the ex vivo perfused lung consisted of (1) blood gas analysis of inflow and outflow blood at 10-minute intervals; (2) continuous pulmonary artery and airway pressure monitoring; (3) measurement of pulmonary venous oxygen tension after 1 hour of reperfusion, with inflow oxygen tension adjusted to 15 mm Hg; (4) wet/dry weight ratio. We conclude that the paracorporeal circuit does not, in itself, cause lung injury over a 1-hour period; lungs preserved with nitrogen inflation rapidly became edematous and failed to function on reperfusion. Preservation with 100% oxygen inflation appears superior to inflation with room air.

Surveillance study of diltiazem use in black and nonblack angina patients

Diltiazem hydrochloride was studied in 133 patients with angina to determine whether differing effects were produced in black patients (39 percent of patients) as compared with nonblack patients. The antihypertensive effect of the drug was also assessed. No statistically significant differences between the responses of blacks and nonblacks were found in the reduction of angina frequency (54 percent of blacks improved, 58 percent of nonblacks), nitroglycerin consumption (60 percent of blacks used less, 66 percent of nonblacks), and changes in lifestyle, as measured with the New York Heart Association scale (55 percent of blacks improved, 63 percent of nonblacks). The antihypertensive effects (not analyzed by race) were greatest in patients with uncontrolled hypertension. Average decreases in this group were 18 mmHg in supine systolic pressures and 14 mmHg in supine diastolic pressures, as compared with decreases of only 4 and 3 mmHg in normotensives. Study results suggest that there is a difference in the type of angina afflicting blacks and nonblacks, that hypertension more often accompanies angina in blacks, and that diltiazem is equally effective in treating angina in blacks and nonblacks.

Rapid determination of 5-fluorocytosine levels in blood

Levels of 5-fluorocytosine in blood were rapidly calculated by determining the amount of competition in the creatinine iminohydrolase (creatinine deiminase; EC 3.5.4.21) assay for creatinine with the Kodak Ektachem system (Eastman Kodak Co., Rochester, N.Y.). The correlation with bioassay values was extremely high (r = 0.982). Standards and samples were highly stable over time.

Abnormalities in the vagus nerve in canine acrylamide neuropathy

Dogs exposed to acrylamide develop a sensorimotor peripheral neuropathy and megaoesophagus. The presence of neuropathy was confirmed electrophysiologically and histologically. Hindlimb motor conduction velocity was reduced and there was a loss of large diameter myelinated fibres in the dorsal common digital nerve and the tibial nerve. The conduction velocity of vagal motor fibres innervating the thoracic oesophagus was not decreased; there was a reduction in the conduction velocity of the mixed nerve action potential of the vagus. Degenerating nerve fibres were observed in the vagus in the midthoracic region. The damage to vagal nerve fibres may be an important factor in the causation of megaoesophagus.

Presynaptic alpha-adrenoceptor blocking properties among tri- and tetra-cyclic antidepressant drugs

1 The effect of various antidepressants (5 x 10(-8) to 2 x 10(-5) M) on the resting overflow of tritium, on the evoked overflow and the contractile response to electrical stimulation (2.5 Hz, 2.0 ms) has been determined in mouse vas deferens previously incubated with [(3)H]-(-)-noradrenaline.2 Mianserin and ORG GC 94 produced a concentration-dependent increase of more than two fold in the electrically evoked overflow and the contractile response and, at the highest concentration, slightly increased resting release. These effects were largely unchanged in the presence of a concentration of cocaine effective in blocking noradrenaline uptake (1.1 x 10(-5) M).3 The ability of phentolamine (1 x 10(-5) M) to increase both the evoked overflow of tritium and the contractile response was greatly reduced when these parameters were already elevated by the presence of mianserin or ORG GC 94.4 The inhibitory effect of exogenous (-)-noradrenaline on evoked overflow was greatly reduced in the presence of mianserin or ORG GC 94 (4 x 10(-6) M).5 The inhibitory effect of clonidine on the twitch response of the mouse vas deferens was antagonized by mianserin and ORG GC 94 in a competitive manner (pA(2) values 7.3 and 7.1 respectively).6 Maprotiline, desipramine and nortriptyline (> 3 x 10(-6) M) produced a parallel fall in both evoked tritium overflow and in the contractile response and increased the resting overflow at higher concentrations. These effects were largely unchanged in the presence of cocaine (1.1 x 10(-5) M).7 Doxepin, imipramine and iprindole all increased resting overflow at high concentrations (2 x 10(-5) M) but produced only small changes in evoked overflow and in the contractile response at lower concentrations.8 It is concluded that mianserin and ORG GC 94 produce a blockade of presynaptic alpha-adrenoceptors which could contribute to an antidepressant effect but that this type of action is not common to all antidepressants.

The effect of stimulus intensity on alpha-adrenoceptor-mediated feedback control of noradrenaline release

1 Mouse vas deferns stimulated transmurally (2.5 Hz, 2-32 V, 40-620 mA, FOR 45 s) responded with a twitch and a secondary contraction. Both responses were abolished by cinchocaine and were voltage-dependent. 2 In tissues previously incubated with (3H)-(--)-noradrenaline, stimulation also produced an increase in tritium overflow from the tissue. Phentolamine increased tritium overflow by 19% at high stimulus intensities (30 V, 600 mA) and by 130% at low stimulus intensities (11 V, 200 mA). 3 It is concluded that alpha-adrenoceptor-mediated feedback control of noradrenaline release is more marked at low stimulus intensities and that this is compatible with a role for calcium ions in this control mechanism.

Possible differences in alpha-adrenoceptors in rabbit ileum and spleen

In isolated tissues from reserpinized rabbits (5 mg kg-1, i.m. 20 h before experiment) and in the presence of cocaine (3 x 10(-5) M), corticosterone (2.8 x 10(-5)M), tropolone (3 x 10(-5) M), propranolol (4 x 10(-5)M) and disodium EDTA (3 X 10(-5)M), the potency ratios (relative to (-)-noradrenaline) of (-)adrenaline, (-)-phenylephrine and (+/-)-methoxamine were (m+/-s.e.) 2.03 +/- 0.13, 0.045 +/- 0.003 and 0.0062 +/- 0.0018 respectively in splenic strips and 1.77 +/- 0.41, 0.093 +/- 0.018 and 0.029 +/- 0.004 respectively in isolated ileum. Although the pA2 values for phentolamine and thymoxamine against (-)-noradrenaline in the two tissues were very similar there was a statistically significant difference when using yohimbine as the alpha-adrenoceptor blocking agent (pA2 = 6.80 +/- 0.30 in spleen; 5.60 +/- 0.12 in ileum). These differences suggest that the alpha-adrenoceptor in the two tissues is not identical. The pA2 value of phentolamine in rabbits ileum was not significantly different whether (-)noradrenaline or (+/-) methoxamine was used as agonist (7.91 +/- 0.07 and 7.97 +/- 0.06 respectively) while that of yohimbine was 5.56 +/- 0.10 using (-)noradrenaline and 6.19 +/- 0.12 using (+/-)methoxamine. In the light of this latter result and, considering the scatter of the experimentally determined values, there may be two alpha-adrenoceptors in rabbit ileum and either or both may not be identical in all respects to the alpha-adrenoceptor found in rabbit spleen.

A comparison in rabbit isolated hearts of the dysrhythmogenic potential of amitriptyline, maprotiline and mianserin in relation to their ability to block noradrenaline uptake

1. In isolated hearts of rabbits, perfusion with (-)-noradrenaline (0.0059 to 5.9 micronM) resulted in chronotropic and inotropic responses and a shortening of the interval between peak atrial and peak ventricular tensions (the A-V contraction interval). No dysrhythmias developed but at higher concentrations (590 micronM) 2 out of 7 hearts developed dysrhythmias (extrasystoles). 2. Perfusion with the antidepressants amitriptyline or maprotiline (4.8 micronM) or mianserin (28.8 micronM) reduced ventricular force, did not change heart rate and only amitriptyline reduced atrial force and lengthened the A-V contraction interval. At 4.8 micronM mianserin produced only a marginal shortening of the A-V contraction interval. 3. At these concentrations no dysrhythmias developed but at higher concentrations (amitriptyline 8 micronM, maprotiline 8 micronM, mianserin 60 micronM) all the agents produced dysrhythmias involving an interference with atrio-ventricular synchronization. 4. In the presence of mianserin (4.8 micronM) perfusion with noradrenaline (0.0059 to 5.9 micronM) shortened the A-V contraction interval and did not produce dysrhythmias. In the presence of amitriptyline or maprotiline (4.8 micronM) or mianserin (28.8 micronM) the A-V contraction interval generally lengthened and most hearts developed dysrhythmias (usually involving interference with atrio-ventricular synchronization). 5. [3H]-(-)-Noradrenaline uptake in perfused rabbit hearts and in mouse isolated atria or vasa deferentia was inhibited by the antidepressants to a similar extent, amitriptyline being marginally most potent (molar potency taken as 1.0), maprotiline being less potent (1.5) and mianserin least potent (2.0)). 6. It is concluded that of these three antidepressants, mianserin is least cardiotoxic in this preparation and that the ability of these antidepressants to predispose to noradrenaline-induced dysrhythmias is not related to blockade of noradrenaline uptake.

Possible subdivisions among alpha-adrenoreceptors in various isolated tissues

The ratio (expressed in log10 units) of the equieffective concentrations of (+)- and (-)-noradrenaline has been measured in a variety of isolated tissues in the presence of cocaine (1 x 10(-5) M), tropolone (3 x 10(-5) M) and (+/-)-propranolol (5 x 10(-7) to 5 x 10(-5) M). The values obtained fall into 3 distinct and statistically different groups. Firstly, a high group comprising (mean +/- s.e.) mouse vasdeferens (2-78 +/- 0-04), rabbit duodenum (2-91 +/- 0-07) and ileum (2-86 +/- 0-05). Secondly a middle group comprising rabbit vas deferens (2-54 +/- 0-04), bladder neck muscle (2-56 +/- 0-07) and spleen 2-50 +/- 0-02), guinea-pig vas deferens (2-55 +/- 0-10) and bladder neck muscle (2-48 +/- 0-13) and rat deferens (2-40 +/- 0-08) and thirdlya low group comprising the bladder detrusor muscle from both the rabbit (2-08 +/- 0-08) and the guinea-pig (2-07 +/- 0-04). Under the same conditions measurement of pA2 values for phentolamine and piperoxan against noradrenaline gave the following values in rat vase deferens (8-22 +/- 0-07 and 6-72 +/- 0-03 respectively) and mouse vas deferens (8-31 +/- 0-05 and 6-53 +/- 0-07 respectively). The results are discussed in relation to other findings conderning the nature of the alpha-adrenoreceptor in these tissues. In spite of the absence of any significant difference between the potency of the alpha-adrenoreceptor blocking agents in the two species it is suggested that alpha-adernoreceptors may not belong to a single homogenous population but may vary in their characteristics from tissue to tissue.